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Re: Ontology Mapping

From: Drew McDermott <drew.mcdermott@yale.edu>
Date: Mon, 31 Mar 2003 14:02:43 -0500 (EST)
Message-Id: <200303311902.h2VJ2hA06094@pantheon-po04.its.yale.edu>
To: www-rdf-logic@w3.org


   Reply-To: <hagenstonmd@sbcglobal.net>
   From: <hagenstonmd@sbcglobal.net>
   Date: Wed, 26 Mar 2003 13:21:05 -0800

   I would welcome any advice/comments on Ontology Mapping.  I am trying to =
   put together an exemlar that demonstrates how an Articulation Ontology =
   works.

   My question is in reference to Chapter 4 in the Web Ontology Language =
   Guide Version 1.0 dtd 10 Feb 2003 Ontology Mapping.

   Assuming you have two separate ontologies (O1, O2) both having separate =
   conceptualizations you wish to adopt.  In order to extend the desired =
   conceptualizations,  a separate Articulation Ontology is established to =
   articulate/map the desired conceptualizations from both sources.  In =
   order for this concept to work would the Articulation Ontology first be =
   required to import O1 and O2 before declaring that O1 ClassA =
   equivalentClass  O2 ClassB ?  Or is it a better practice to precede the =
   mapping statement in the Articulation Ontology with the URL of each =
   equivalent class and not bother with the import allowing the URL to =
   point to the location(s) of the equivalent classes? =20

You could do it either way.  The first is called "merging" the two
ontologies, i.e., producing an ontology that is the union of the two
plus further axioms that express the relationships among their symbols.
The second one might call "syntax mapping," since it treats the
component ontologies as entities to be referred to, not used.

The OWL guide
(http://www.w3.org/TR/2002/WD-owl-guide-20021104/#OntologyMapping) 
is talking about the merging approach.

   Also, according to the reference, it is more efficient to
   articulate as  "high up" the class hierarchy as possible, meaning
   once it is stated  that two classes are equivalent, by definition
   all their members must  satisfactorily belong to both classes.

Where exactly does it talk about how high up the articulation is?

   Would this obviate the  requirement for a similar articulation at
   the instance level as long as  the user subscribed to the higher
   up Articulation Ontology?  What harm  would the redundancy cause
   if mappings at both levels occurred?

I don't see how it would obviate lower-level matchings.  If ontology 1
lists a bunch of horses, and ontology 2 lists a bunch of equines,
merely knowing that "horse" and "equine" are the same class doesn't
tell you which horse in list 1 is the same as which horse in list 2
(if any in fact are the same).

-- 
                                             -- Drew McDermott
Received on Monday, 31 March 2003 14:03:01 GMT

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